Abstract: Water for irrigation at Mohave Valley Irrigation and Drainage District (MVIDD) is all pumped from the alluvial aquifer along the Arizona eastern side of the Colorado River. This groundwater pumping is administered as diversion from the Colorado River under a contract between the MVIDD and the US Bureau of Reclamation (Reclamation). Previous efforts to measure pumped flows have been largely unsuccessful due to multiple factors including corrosive agents present in the water, limited head availability and/or limited space availability for proper installation and operation of traditional canal measurement structures.
Corrosive agents present in the pumped water have limited the service life for the various flow measurement technologies tried on District pumps. Open channel measurement structures that have been installed at selected sites as part of flow measurement demonstration efforts have met with limited success. Insufficient space between pump discharge and field turnouts or lateral off-takes is a problem for open channel structures at multiple sites. Available freeboard along lined canal sections has proven insufficient for even long-throated flumes, which pose the least head requirements of all critical-flow open channel flow measurement structures.
In an effort to address this challenge, Reclamation’s Water Conservation Field Services Program of the Yuma Area Office (YAO) worked with Reclamation’s Hydraulic Investigation and Laboratory Services group (HILS) to devise a plan for measuring flow from each well within MVIDD using technologies that would have an acceptable service life and be cost-effective for an agricultural water system. A combination of venturi-type pipe meters and open channel flumes utilizing the venturi solution for either critical flow or submerged operation – all using bubbler sensors to minimize potential for sensor degradation due to contact with corrosive agents in the water – was devised for MVIDD. Installation of measurement equipment was performed by MVIDD staff in Spring and Summer of 2010. Reclamation began performing calibrations of measurement sites during Fall of 2010. Calibrations are expected to be completed by summer of 2011. When calibrations are completed, flow data will be telemetered real-time by radio from each site to the MVIDD office.